A forthcoming book by a pair of New York Times reporters says there has been notable "tension" between President Biden and former President Barack Obama, and that House Speaker Nancy Pelosi, D-Calif., even described the former president as "jealous" of his Democratic successor.

An excerpt of the new book, "This Will Not Pass: Trump, Biden, and the Battle for America's Future" by Alexander Burns and Jonathan Martin, obtained by Fox News Digital, alleges that Obama had "complicated feelings" about Biden being president.

BIDEN'S WHITE HOUSE SENIOR ADVISER CALLED ‘SQUAD’ MEMBERS ‘F---ING IDIOTS’: BOOK

U.S. President Joe Biden and former President Barack Obama

U.S. President Joe Biden and former President Barack Obama attend an event to mark the 2010 passage of the Affordable Care Act in the East Room of the White House on April 5, 2022 in Washington, DC.  (Photo by Chip Somodevilla/Getty Images)

According to the book, which will be released next Tuesday, Obama and Biden spoke by phone "occasionally" at the outset of Biden’s presidency, and their conversations were "hardly the stuff of the tight brotherhood both men had sold to the country as a cheery political fable."

"Nancy Pelosi, who spoke regularly with the former president, came away from her conversations with Obama during this period with a matter-of-fact diagnosis. She told a friend: ‘Obama is jealous of Biden,’" the book alleges.

Former President Barack Obama hugs Speaker of the House Nancy Pelosi (D-CA)

Former President Barack Obama hugs Speaker of the House Nancy Pelosi (D-CA) at the end of an event to mark the 2010 passage of the Affordable Care Act in the East Room of the White House on April 5, 2022 in Washington, DC. 

According to his adviser, Biden said, "I am confident that Barack is not happy with the coverage of this administration as more transformative than his," the book alleges.

Despite the best-friend bond with Obama that Biden often touted on the campaign trail, lingering tensions between the two statesmen over their vastly different governing styles were exposed in an August 2020 Politico report.

The Politico report said a number of anonymously sourced quotes from Obama leaked out throughout the 2020 Biden campaign where the former president allegedly expressed doubts about his former running mates’ fitness for office.

Clyburn, a top Democrat in Washington, was perhaps the most pivotal figure for President Biden's 2020 campaign.

Clyburn, a top Democrat in Washington, was perhaps the most pivotal figure for President Biden's 2020 campaign. (AP Photo/Carolyn Kaster)

"Don’t underestimate Joe’s ability to f--k things up," one Democrat who spoke to the former president recalled him saying.

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And while some senior Democrats credited Biden’s ties to Obama for his strong relationship with Black voters, Biden said he earned their votes all on his own, telling aides after his South Carolina primary win Obama hadn’t "lifted a finger" to help him, Politico reported.

The White House and the offices of Obama and Pelosi did not respond to Fox News Digital's requests for comment.

Fox News’ Morgan Phillips contributed to this report.